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![Figure 12 ship4013.jpg Figure 12](/sites/default/files/styles/max_1300x1300/https/s3.amazonaws.com/s3-east-testmedia-noaa.woc.noaa.gov/dam/Photos/legacy/pl23_ship4013.jpg?itok=spOXLCQy)
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Figure 12. E. B. Helland-Hansen's photometer. Left: device before opening.Middle: Device during exposure. Right: Device after closing. Invented by Bjorn Helland-Hansen in 1910, this photometer was used aboard the MICHAEL SARSin the North Atlantic. It was first used near the Azores at depths of 500 to700 meters. (Image credit: Oceanographic Museum of Monaco | P. Roggero)